This invention relates to fastener setting tools and more particularly to fastener setting tools having offset nose assemblies.
Fastener tools having offset nose assemblies are required to provide access to fasteners located between closely spaced panels or within small clearance spaces. The offset nose assembly may include, for example, an anvil and a collet for swaging a fastener collar about a grooved fastener pin. In such designs the swaging anvil is radially offset from the axis of the piston which drives the anvil against the collet. This arrangement allows the radially offset anvil portion of the nose assembly to access the fasteners without interference from the anvil housing and/or from tile main body of the tool.
By offsetting the axis of the fastener pin and collar assembly from the primary power axis of the tool, large bending forces are generated at the nose assembly during swaging of the collar around the pin. These bending forces tend to generate deflection between the anvil and collet as well as deflection of the entire nose assembly with respect to the body Of the tool and with respect to the pin and collet. This deflection can cause binding of the collet within the anvil housing and can cause premature or uncontrolled pin breakage.
Various attempts have been made to address these deflection problems but all of the prior art attempts to address this problem have suffered from one or more disadvantages. Specifically, the prior art devices have attempted to prevent the deflection forces by the use of bulky, massive components, thereby detracting from the portability of the tool and thereby limiting the ability of the tool to access small spaces; and/or the prior art devices have attempted to prevent the deflection forces by utilizing threaded connections which are difficult if not impossible to precisely control in a mass production environment.